It is well known that pieces of certain pure metals, namely iron, cobalt and nickel can be treated in such a way that their magnetic moments or domains become aligned and said pieces then behave as magnets, that is they acquire a magnetic field within which magnetic materials may be influenced as to their energy content and potential. The strength of the field increases according to the percentage of the domains present and those aligned. The field can be further increased by the addition of other metals or their oxides to form magnetic alloys, for example barium, boron, copper, neodymium, promethium and samarium. Tri-alloys can also be formed further increasing the field strength, for example, neodymium-iron-boron. Another group of suitable magnetic materials is called ferrites. These consist of the oxides of iron to which small quantities of transition metal oxides; for example, cobalt or nickel have been added. These are known as spinel ferrites and have the general formula M(OFe.sub.2 O.sub.3) where M is a divalent transition ion. Another form of ferrite is iron oxide to which the oxides of the reactive metals strontium or barium have been alloyed. Ferrites are particularly useful because they are easily reduced to a powder and can be reformed to suitable shapes by compaction or as a component of a plastic or ceramic compound. Such reconstituted ferrite particles when part of a ceramic compound produce a magnet with a surface hardness as high as 70 on the Shore D scale. When incorporated in a plastic the hardness is reduced generally to around 90 on the Shore A scale and as a rubber component the reading is about 60 on the Shore A scale. Plastic and rubber based magnets can be made flexible if cast in very thin section in which case, however, the field strength is usually impracticably low. To overcome this the magnetic sheet is often rolled to form a round or square section tube. The result is almost a total loss of cross-sectional flexibility but retaining such longitudinal flexibility as to make them useful for gaskets including domestic appliances such as refrigerators where curvature is gentle and sharp bends are catered for by miter jointing. Thin flat magnets of low field strength find a use as markers on a magnetic indicator board, in children's toys and as decorative refrigerator magnets which sometimes double as note-holders. It has been found that magnets of higher strength that is of thicker cross section are capable of attracting the hemoglobin content of erythrocytes present in blood plasma. Such magnets have been strategically placed in medical devices to attract erythrocytes to various parts of the body to increase the oxygen supply to that point. These points are often nerve endings and are sometimes described in Oriental medicine as pressure or acupuncture points. Magnets are embedded in or attached to rubber, plastic, cloth or other materials to hold them in place. It will be seen that these magnets are necessarily small in diameter, comparatively large in cross section and of hardness at least measurable as 50 on the Shore A scale. Such magnets must be cushioned if they are placed near to soft tissue. Any barrier will reduce the field strength of a magnetic source. The magnets are always discernable and often uncomfortable especially when used in footwear and more especially on the upper regions of footwear insoles where loads are heavy and vertically applied. Furthermore, it will be seen that these discreet magnet areas of high compression combined with the magnetic attraction directed towards the hemoglobin can slow the blood to such an extent as to encourage vascular restriction or clotting. When the hemoglobin becomes met-hemoglobin, that is the oxide has degenerated from ferrous ({character pullout}) to ferric ({character pullout}) a localized area of cyanosis may be caused due to lack of oxygen. Clotting in this region could prove fatal. Such quasi (or alternative) medical devices include shoe insoles, elbow, knee, spinal and neck pads.